pglogical 2 =========== The pglogical 2 extension provides logical streaming replication for PostgreSQL, using a publish/subscribe model. It is based on technology developed as part of :ref:`EDB Postgres Distributed ` . .. Note "pglogical 2 is open source":: EDB maintains pglogical as a service to the PostgreSQL community. For license and copyright information, or for access to the source, visit the project page at https://github.com/2ndQuadrant/pglogical We use the following terms to describe data streams between nodes, deliberately reused from the earlier Slony technology: - Nodes - PostgreSQL database instances - Providers and Subscribers - roles taken by Nodes - Replication Set - a collection of tables pglogical is utilising the latest in-core features, so we have these version restrictions: - Provider & subscriber nodes must run PostgreSQL 9.4+ - PostgreSQL 9.5+ is required for replication origin filtering and conflict detection - Additionally, subscriber can be Postgres-XL 9.5+ Use cases supported are: - Upgrades between major versions (given the above restrictions) - Full database replication - Selective replication of sets of tables using replication sets - Selective replication of table rows at either publisher or subscriber side (row_filter) - Selective replication of table columns at publisher side - Data gather/merge from multiple upstream servers Architectural details: - pglogical works on a per-database level, not whole server level like physical streaming replication - One Provider may feed multiple Subscribers without incurring additional disk write overhead - One Subscriber can merge changes from several origins and detect conflict between changes with automatic and configurable conflict resolution (some, but not all aspects required for multi-master). - Cascading replication is implemented in the form of changeset forwarding. .. toctree:: :maxdepth: 3 release-notes requirements installation usage synchronous-replication conflicts configuration-options limitations-and-restrictions